Dual IF Digital Variable Gain Amplifier

10 – 500 MHz IDTF1241NBGI

IDT FlatNoise

18

Rev O Nov 2012

IDTF1241

DATASHEET

N

The result is that the F1241 with its unique noise contour will improve SNR significantly in this multi-carrier

B at high attenuation settings which allows for the

use of a lower cost / lower resolution ADC in the Rx path. Alternately, F1241 FlatNoise

excellent H2, IM2, and H3 performance allows simplification or even elimination of the Anti-Alias Filter.

-130

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

10

0

40

80

120

160

200

240

280

320

360

400

440

Frequency (MHz)

Digital

Downconversion BW

1st Nyquist Zone =

0 to

SAMP

30 dB filtering for

H2 and IM2

products

Sample Rate ~ 160 MHz

Chebyshev Discrete LC

filter 3rd order

3rd Nyquist Zone =

Zone4 Alias noise

rejection only ~ 3 dB

Zone2 Alias

noise rejection

only ~ 6 dB

Multi-Carrier

BW = 170 to 230

MHz

2nd Nyquist Zone =

4th Nyquist Zone =

1.0

3.0

5.0

7.0

9.0

11.0

13.0

0

4

8

12

16

20

24

VGA Attenuation below Max Gain (dB)

Standard VGA w/14 bit ADC

F1240/1 w/14 bit ADC

F1240/1 w/12 bit ADC

Up to 2.1 dB advantage

in SNR!

Enables use of low cost

12-bit ADC with no loss

of performance

SNR @ 200 MHz

with 165 fsec clock

jitter = 69.3 dB

SNR @ 200 MHz

with 165 fsec clock

jitter = 67.7 dB